In general, an electrical interrupt device (e.g., a circuit breaker) operates to engage and disengage a selected electrical circuit from an electrical power supply. The electrical interrupt device ensures current interruption thereby providing protection to the electrical circuit from unwanted electrical conditions, such as continuous over-current conditions and high current transients due, for example, to electrical short circuits. Such electrical interrupt devices operate by separating a pair of internal electrical contacts contained within a housing of the electrical interrupt device.
Typically, one electrical contact is stationary, while the other is movable. Conventional circuit breakers may include a moving electrical contact mounted on an end of a moving (e.g., pivotable) contact arm, such that the moving electrical contact moves through a separation path. Contact separation between the moving and stationary electrical contacts may also occur manually, such as by a person throwing a handle of a circuit breaker or other electrical interrupt device. This throw action may engage an operating mechanism, which may be coupled to the contact arm and the moveable movable contact. Otherwise, the electrical contacts may be separated automatically when an persistent over-current condition or a short circuit condition is encountered. This automatic tripping may be accomplished by a tripping mechanism actuated via an overload element (e.g., a bimetal element and/or a magnet).
Upon contact separation of the electrical contacts by tripping (manual or automatic) of the circuit breaker, a substantial electrical arc may be formed between the electrical contacts. It is desirable to extinguish this electrical arc as quickly as possible to avoid damaging internal components of the electrical interrupt device. However, in previous devices such as circuit breakers, for example, although extinguishment of such arcs has been effective, the arc may not have been extinguished as rapidly as desired.
Accordingly, there is a need for electrical interrupt devices, electrical device contact assemblies, and methods of operating electrical interrupt devices that offer better arc extinguishment following electrical contact separation.